The invention relates to an optical polarimetric detector making it possible to detect two polarizations and, at the same time, eliminating the background noise.
The object of the present invention is to describe the architecture making it possible to combine two specific functionalities already demonstrated by quantum well detectors; the possibility of producing bispectral devices (French patent No. 2 756 667) and the possibility of producing detectors integrating, in the active layer, the function of subtracting the continuous component, that is to say the dark current of thermal origin and the optical scene current (French patent No. 2 756 666). Each of these two functions requires a double stack of quantum wells and three stage connector technology. The invention makes it possible to keep this number of stacks and of connector technology stages, while making it possible to read in subtractive mode and according to three, vertical (V), horizontal (H) and mixed (V+H) polarimetric templates.
The invention therefore relates to a bifunctional optical detector comprising:
a first active detector element having a photoconductor with which a first diffraction grating is associated allowing incident light from a first specific polarization direction to be coupled in the first detector element and allowing the latter to detect the light having this first polarization direction;
a second active detector element having a photoconductor with which a second diffraction grating is associated allowing incident light from a second polarization direction to be coupled in the second detector element and allowing the latter to detect the light having this second polarization direction.
The invention also relates to a method of producing such a detector.